dual-loop

name	dual-loop
aliases	["Sequential Agent","Agent as a Tool"]
description	(Industry standard: Sequential Agent / Agent as a Tool) Primary Use Case: Delegating a well-defined task to a worker agent, verifying its execution, and repeating if necessary. Inner/outer agent delegation pattern. Use when: work needs to be delegated from a strategic controller (Outer Loop) to a tactical executor (Inner Loop) via strategy packets, with verification and correction loops.
allowed-tools	Bash, Read, Write

Dual-Loop (Inner/Outer Agent Delegation)

This skill defines the orchestration pattern for the Dual-Loop Agent Architecture. The Outer Loop (the directing agent) uses this protocol to organize work, delegate execution to an Inner Loop (the coding/tactical agent), and rigorously verify the results before merging.

This architecture is entirely framework-agnostic and can be utilized by any AI agent pairing (e.g., Antigravity directing Claude Code, or an OpenHands agent directing a specialized CLI sub-agent).

CRITICAL: Anti-Simulation Rules

YOU MUST ACTUALLY PERFORM THE VALIDATIONS LISTED BELOW. Describing what you "would do" or marking a step complete without actually doing the verification is a PROTOCOL VIOLATION.

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Architecture Overview

flowchart LR
    subgraph Outer["Outer Loop (Strategy & Protocol)"]
        Scout[Scout & Plan] --> Spec[Define Tasks]
        Spec --> Packet[Generate Strategy Packet]
        Verify[Verify Result] -->|Pass| Commit[Seal & Commit]
        Verify -->|Fail| Correct[Generate Correction Packet]
    end

    subgraph Inner["Inner Loop (Execution)"]
        Receive[Read Packet] --> Execute[Write Code & Run Tests]
        Execute -->|No Git| Done[Signal Done]
    end

    Packet -->|Handoff| Receive
    Done -->|Completion| Verify
    Correct -->|Delta Fix| Receive

Reference: Architecture Diagram

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The Workflow Loop

Step 1: The Plan (Outer Loop)

1. Orientation: The Outer Loop agent reads the project requirements or goals.
2. Decomposition: Break the goal down into distinct Work Packages (WPs) or sub-tasks.
3. Verification: Confirm that the tasks are atomic, testable, and do not overlap.

Step 2: Prepare Execution Environment

1. Isolation: Ensure a safe workspace exists for the Inner Loop. Workspace creation (e.g., worktrees, branching, ephemeral containers) is strictly a delegated responsibility of the Orchestrator or external tooling. The Dual-Loop just receives the environment.
2. Update State: Mark the current Work Package as "In Progress" in whatever task-tracking system the project uses.

Step 3: Generate Strategy Packet (Outer Loop)

1. Write a tightly scoped markdown document (the "Strategy Packet") specifically for the Inner Loop.
2. Requirements for the Packet:
   • The exact goal.
   • A Pre-Execution Workflow Commitment Diagram (an ASCII box) mapping out the steps the Inner Loop must take.
   • Only the specific file paths the sub-agent needs to care about.
   • Strict "NO GIT" constraints (the Inner Loop must not commit).
   • If generating scripts/pipelines, instruct the Inner Loop to use the "Modular Building Blocks" architecture (split convenience CLI wrappers from core Python APIs).
   • Clear Acceptance Criteria.
3. Save the packet (e.g., handoffs/task_packet_001.md).

Step 4: Hand-off (The Bridge)

The Outer Loop invokes the Inner Loop. Depending on the environment, this is either done by spawning a sub-process (e.g., claude "Read handoffs/task_packet_001.md"), calling an API, or asking the Human User to switch terminals.

Step 5: Execute (Inner Loop)

The Inner Loop agent:

1. Reads the packet.
2. Writes the code.
3. Runs the tests.
4. Signals "Done" when the Acceptance Criteria are met (or if it gets fundamentally stuck).

Constraint: The Inner Loop MUST NOT run version control commands.

Step 6: Verify (Outer Loop)

Once the Inner Loop signals completion, the Outer Loop must verify the results:

1. Delta Check: Inspect the changes (e.g., via diff tools or system state checks) to see what the Inner Loop actually altered.
2. Test Check: Run the test suite mechanically to ensure nothing broke.
3. Lint Check: Validate the syntax.

On Verification PASS:

1. The Outer Loop accepts the changes.
2. The task tracker is updated to "Done".

On Verification FAIL:

1. The Outer Loop generates a Correction Packet using the strict Severity-Stratified Output Schema:
   • 🔴 CRITICAL: The code fails to compile, tests fail, or the requested feature is entirely missing.
   • 🟡 MODERATE: The feature works, but violates project architecture, ADRs, or performance standards.
   • 🟢 MINOR: The feature works and follows architecture, but has minor naming or stylistic issues.
2. The Outer Loop loops back to Step 4, handing the Correction Packet to the Inner Loop.

Step 7: Completion & Handoff

Once all Work Packages are verified, the Dual-Loop pattern is complete. The Outer Loop terminates and returns control to the global lifecycle manager (Orchestrator) for Retrospectives and ecosystem sealing.

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Task Lane Management

Throughout the process, the Outer Loop must maintain discipline over task states. If you are operating this loop, you must ensure you or the task tracker accurately reflects:

1. Backlog -> Doing (When Strategy Packet is generated)
2. Doing -> Review (When Inner Loop signals completion)
3. Review -> Done (When Outer Loop verifies and commits)
4. Review -> Doing (If verification fails and a Correction Packet is sent)

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Workspace Isolation

Dual-Loop (Agent-Loops) does not manage workspaces. It receives an isolated directory or execution context from the Orchestrator and runs the loop inside it. Workspace creation (e.g., git worktrees, branches) is a delegated responsibility of the Orchestrator or the global system environment.

Fallback: In-Place Execution

If an isolated workspace cannot be provided:

1. The Inner Loop codes directly in the main directory.
2. The Outer Loop must log this lack of isolation in a friction log for the handoff to the Orchestrator.
3. All other constraints (no system manipulation from Inner Loop out of scope, verification gate, correction packets) still apply.

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Fundamental Constraints

• No Protocol Crossing: The Inner Loop manages tacticals (code compilation, tests). The Outer Loop manages strategy (git, architecture decisions, human interactions).
• Isolation: Strategy Packets must be minimal. Do not send the Inner Loop thousands of lines of conversation history. Give it exactly what it needs to execute the specific Work Package.